JPH0514256Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a lens unit having two or more of a plurality of lenses and an aperture, and particularly to a lens unit using an ultrasonic motor.

(Prior Art) For example, many recent camera lens assemblies have power zoom, autofocus, and auto iris. Furthermore, recent camera lenses tend to be smaller and lighter. In conventional camera lens assemblies, electromagnetic motors and IG meters are used for each mechanism to drive mechanisms such as power zoom, auto focus, and auto iris, and deceleration mechanisms and power transmission mechanisms are required. The structure is complicated and the price is high, and the shape of the electromagnetic motor means that these mechanisms are placed outside the lens, making it difficult to miniaturize.

On the other hand, recently, a motor called an ultrasonic motor that obtains driving force by using elastic waves generated by a piezoelectric element has appeared. Due to its structure, this motor
It is thin and can be made into a ring shape.

(Purpose) The present invention uses an ultrasonic motor to drive a lens unit having two or more of a plurality of lenses and an aperture, thereby eliminating a deceleration mechanism and a power transmission mechanism that were conventionally necessary. By arranging two or more ultrasonic motors along one substrate arranged perpendicular to the optical axis and fixing them to the substrate, the device or equipment can be made compact and unnecessary. The aim is to make it possible to reduce the size and weight of the vehicle.

(Example) First, a conventional example of a camera lens assembly having auto focus, power zoom, and auto iris will be explained with reference to FIG. 1. In the figure, 1 is a focusing lens, and 2 is a focusing lens barrel. ,
3 is a fixed lens barrel with a helicoid screw on the outer periphery;
A focusing lens barrel 2 is screwed and held. 4 is an electromagnetic motor for autofocus, 5 is a gear fixed to the output shaft of the motor 4, 6 is a gear that meshes with the gear 5, 2a is a gear cut on the outer periphery of the focusing lens barrel 2, and these gears 2a, 6, and 5 mesh with each other, and as the motor 4 rotates, the focusing lens barrel 2 rotates and moves back and forth, thereby moving the focusing lens 1. Reference numeral 7 denotes a zoom cam ring, which is rotatably held within the fixed barrel 3 and is controlled in the optical axis direction by a lens base plate 8 fixed to the rear end of the fixed barrel 3 and a front plate 9 fixed to the front end. Movement is restricted. The cam ring 7 is provided with cam grooves 7a, 7b.
pins 14 and 1 are implanted in movable rings 12 and 13 that hold the variable magnification lens 10 and the correction lens 11, respectively.
5 are engaged with each other, and these movable rings 12 and 13 are engaged with linear guide bars 16a and 16b, and when the cam ring 7 rotates, they move in the optical axis direction according to the leads of the cam grooves 7a and 7b, respectively. It's becoming like this. A gear 7c is cut into a part of the outer periphery of the cam ring 7. 1
7 is an electromagnetic motor for zooming, 18 is a gear fixed to the output shaft of the motor 17, and 19 is the gear 18.
A gear 21 meshes with the gear 7c, and is connected to the gear 19 by a shaft 20.
The cam ring 7 is rotated by the rotation of the motor 18, and zooming is performed.

22 is an electromagnetic motor for driving the diaphragm, 23 is the diaphragm, and 22 and 23 together form an IG meter unit.

24 is a relay lens, and 25 is a relay lens barrel.

In the case of a camera lens assembly with the conventional configuration as described above, a complicated deceleration mechanism and power transmission mechanism are required, and due to the structure of the electromagnetic motor, it cannot be placed coaxially with the optical axis of the lens. These mechanisms have to be placed in the camera lens assembly, which hinders the miniaturization of camera lens assemblies.

Next, the structure of the ultrasonic motor will be explained with reference to FIGS. 2 to 5.

In FIG. 2, 101 is a moving element, 102 is a vibrator, and an electrostrictive element 103 is bonded to the vibrator 102. Reference numeral 104 is rubber, which is used to absorb vibrations on the surface opposite to the friction drive surface of the vibrator 102, and to
It is used to pressurize the vibrator 1 and the vibrator 102 so that frictional force can be transmitted between them. 105 is a substrate, which includes a vibrator 102, an electrostrictive element 103, and a rubber 10.
4 are bonded to each other and fixed to the substrate 105.
106 is a steel ball that functions as a thrust bearing. 107 is a spacer for the steel ball 106, 1
A fixing plate 08 is fixed to the substrate 105 with screws 109. FIG. 3 schematically shows an assembled cross-section of the ultrasonic motor shown in FIG. 2. The ultrasonic motor having the structure shown in FIGS. 2 and 3 can take out output from the top surface and the inside of the cylinder as seen in the figures.

In FIG. 4, 101' is a moving element, 102' is a vibrator, 103' is an electrostrictive element, 104' is a rubber, 1
05' is a substrate, and 102', 103', and 104' are bonded to the substrate 105' as in the case of the motor shown in FIGS. 2 and 3. 106' is a steel ball, 107' is a spacer, 108' is a fixing plate, which has a thread cut on the inside, and a screw 1 cut on the top of the board 105'.
05'a and is fixed. FIG. 5 schematically shows an assembled cross section of the motor shown in FIG. 4. The ultrasonic motor having the structure shown in FIGS. 4 and 5 can output power from the outside, upper and lower surfaces of the cylinder as seen in the figures.

FIG. 6 shows an example in which the above-mentioned ultrasonic motor is applied to an aperture unit. In the figure, 207 is a board of an aperture unit fixed to the base of the casing (not shown), and a plurality of pins 207b are implanted on the end surface of a cylindrical portion 207a of the board 207, which will serve as a rotational fulcrum for aperture blades 212, which will be described later. It is set up. 208a
is a comb-shaped substrate attached to the substrate 207, which has comb-shaped electrodes, on which a brush 208b attached to a rotating body 209 (described later) slides, generating pulses corresponding to the amount of movement. It is structured like this. 204 is a felt for absorbing vibrations on the lower surface of the vibrator 202;
3a and 203b are electrostrictive elements. 209 is a rotating plate that is pressed against the vibrator 202 and rotated by elastic waves. A pin 209a for controlling the rotation of the aperture blades 212, which will be described later, is provided on the disk surface of the rotary plate 209.
Several are planted. Further, a brush 208b that slides on the comb substrate 208a is attached to the lower surface of the rotary plate 209 in order to detect the rotation angle of the rotary plate. 209b is the aperture board 20 when the aperture is opened.
Open reset switch mounted on 7
This is a protrusion for turning on the SW. Reference numeral 212 denotes aperture blades arranged between the rotary plate 209 and the fixed body 215, and a plurality of aperture blades 212 are placed on the rotary plate 209 to form an aperture aperture. Arc hole 212a provided in the aperture blade 212, hole 212
The above-mentioned pins 209a and 207b are inserted into the pins 209a and 207b, respectively, and a steel ball 213 and a spacer 214 are interposed therebetween, which function as upper thrust bearings.
07 via a spring 217. At this time,
The screws 216 are attached so as to bias the fixing plate 215 against the aperture base plate 207 by interposing a spring 217 therebetween. By biasing the fixed plate 215, the steel ball 2
The rotary plate 209 is brought into pressure contact with the vibrator 202 through 13, and the rotary plate 20
9 can be driven by friction.

Next, referring to FIGS. 7 to 11, an embodiment of the present invention will be described in comparison with the conventional example shown in FIG. In addition, in FIGS. 7 to 11, the same reference numerals as in FIG. 1 are the same members as described above.

FIG. 7 shows an example in which two of the above ultrasonic motors are arranged on one fixed support member and each is used to drive the power zoom and auto iris described in FIG. An ultrasonic motor 117 as shown in FIGS. 2 to 5 is disposed on the end lens base plate 8, and its mover is glued to the rear end of the zoom ring 7, so that the cam ring 7 can be directly rotated. It is configured. 123 is an aperture unit using the above ultrasonic motor as shown in FIG. 6, and 122 is an ultrasonic motor. Here, the two ultrasonic motors 117 and 122 are both supported by the lens base plate 8, which is a common support member.

FIG. 8 shows an example in which power zoom is driven in the same way as in the example shown in FIG. 7, and an ultrasonic motor is also used to drive autofocus.
15 is an ultrasonic motor; 116 is a ring having a gear cut on its outer periphery; and the ultrasonic motor 115 is provided between the end face of the ring and the base plate 8. In this case, the mover of the motor 115 is glued to the ring 116. A gear 118a meshes with a gear on the outer periphery of the ring 116, a gear 118b is connected to the gear 118a by a rod 118c, and the gear 118b meshes with a gear 2a cut on the outer periphery of the focusing lens barrel 2. The power of the ultrasonic motor 115 rotates the focusing lens barrel 2 and moves it back and forth through these gear trains. Again, both motors 115,1
17 are both supported by the base plate 8.

Note that the configurations shown in FIGS. 7 and 8 may be combined as appropriate, and in that case, three motors 11
7, 122, and 115 are all supported by the base plate 8.

FIG. 9 shows another example of power zoom and autofocus driving. In the figure, 127
is an ultrasonic motor that can output power from the inside of the cylinder (the ones shown in the second and third figures), and its outer base plate is fixed to the inner circumference of the fixed cylinder 3, and the cam ring 7 is driven from the outside. Performs zooming. Autofocus is driven by using an ultrasonic motor 124 whose output can be taken from the outside (the ones shown in Figures 4 and 5), whose inner base plate is fixed to the outer periphery of the fixed cylinder 3, and which is connected to the movable element. The connected helicoid screw member 125 is screwed into a threaded portion 2a cut inside the focusing lens barrel 2, and the lens barrel 2 is driven by the power of the motor 124. Note that the focusing lens barrel 2 will rotate if left as is, so a groove 2b is provided in the lens barrel 2 to prevent rotation, and a fixing barrel 3 is provided to prevent the focusing lens barrel 2 from rotating.
A rotation stopper 3a is attached to the lens barrel 2 so that the lens barrel 2 can only move in the front-rear direction by engagement of the two.

FIG. 10 shows an example in which two ultrasonic motors 32 and 33 are arranged on a donut-shaped substrate 31.

Further, FIG. 11 shows an example of the connection between the donut-shaped substrate 31 having the ultrasonic motor 34 and the aperture unit 35 shown in FIG. 6, for example. Needless to say, the motor portion of the aperture unit 35 is attached to the substrate 31.

By combining a plurality of motors into one unit as shown in FIGS. 10 and 11, the number of parts of the structure into which this unit is incorporated can be reduced, and the assembly process can also be simplified.

(Effects) As explained above, according to the present invention, in the lens unit, two of the plurality of lenses and the aperture are
When driving the above using an ultrasonic motor, a speed reduction mechanism and a power transmission mechanism are unnecessary or simplified. In addition, by arranging two or more ultrasonic motors along one substrate arranged perpendicular to the optical axis and fixing them to the substrate, the device or equipment can be made smaller, more compact, and lighter. becomes possible.

[Brief explanation of the drawing]

Fig. 1 is a sectional view schematically showing an example of a conventional camera lens assembly equipped with auto focus, power zoom, and auto iris, and Figs. 2 and 3 are exploded perspective views showing an example of the structure of an ultrasonic motor. 4 and 5 are exploded perspective views and assembled sectional views showing other structural examples of the ultrasonic motor.
The figure is an exploded perspective view showing an example of an aperture unit using an ultrasonic motor, and FIGS. 7, 8, and 9 show three embodiments in which the present invention is applied to the lens assembly shown in the first figure. A schematic cross-sectional view of a lens assembly;
10 and 11 are perspective views showing two embodiments of a motor unit to which the present invention is applied. 8, 31... Support, 117, 122, 11
5,117,124,127...Ultrasonic motor,
2... Focusing lens barrel, 7... Zoom ring, 123,
35...Aperture unit.

Claims (1)

[Claims for Utility Model Registration] A lens unit comprising two or more of a plurality of lenses 1, 10, 11 and an aperture 23 arranged along the optical axis, two or more of the plurality of lenses and an aperture 23. Two or more driven bodies 7, 116, 209 for driving the above
and two or more ultrasonic motors 115, 117, and 122 for driving the two or more driven bodies, and the two or more ultrasonic motors are connected to one substrate 8 disposed orthogonally to the optical axis. , 9 and fixed to the substrate.